Cree Gmbh

Advanced Technology Materials, Inc.

Jeffrey S Flynn

George R Brandes

Robert P Vaudo

Xueping Xu

Michael Albert Tischler

Joan M Redwing

Barbara E Landini

David Keogh

Duncan W Brown

Huoping Xin

David M Keogh

Michael A Tischler

Hueping Xu

Georges R Brandes

The present invention relates to various switching device structures including Schottky diode, P-N diode, and P-I-N diode, which are characterized by low defect density, low crack density, low pit density and sufficient thickness (&#x3e;2.5 um) GaN layers of low dopant concentration (&#x3c;1E16 cm) grown on a conductive GaN layer. The devices enable substantially higher breakdown voltage on hetero-epitaxial substrates (&#x3c;2 KV) and extremely high breakdown voltage on homo-epitaxial substrates (&#x3e;2 KV).

High voltage switching devices and process for forming same

A III-V nitride homoepitaxial microelectronic device structure comprising a III-V nitride homoepitaxial epi layer of improved epitaxial quality deposited on a III-V nitride material substrate, e.g., of freestanding character. Various processing techniques are described, including a method of forming a III-V nitride homoepitaxial layer on a corresponding III-V nitride material substrate, by depositing the III-V nitride homoepitaxial layer by a VPE process using Group III source material and nitrogen source material under process conditions including V/III ratio in a range of from about 1 to about 10, nitrogen source material partial pressure in a range of from about 1 to about 10torr, growth temperature in a range of from about 500 to about 1250 degrees Celsius, and growth rate in a range of from about 0.1 to about 10microns per hour. The III-V nitride homoepitaxial microelectronic device structures are usefully employed in device applications such as UV LEDs, high electron mobility transistors, and the like.

III-V nitride homoepitaxial material of improved quality formed on free-standing (Al,In,Ga)N substrates

The present invention relates to various switching device structures including Schottky diode, P&#x2014;N diode, and P&#x2014;I&#x2014;N diode, which are characterized by low defect density, low crack density, low pit density and sufficient thickness (&#x3e;2.5 um) GaN layers of low dopant concentration (&#x3c;1E16 cm) grown on a conductive GaN layer. The devices enable substantially higher breakdown voltage on hetero-epitaxial substrates (&#x3c;2 KV) and extremely high breakdown voltage on homo-epitaxial substrates (&#x3e;2 KV).

A III-V nitride, e.g., GaN, substrate including a (0001) surface offcut from the &#x3c;0001&#x3e; direction predominantly toward a direction selected from the group consisting of &#x3c;10-10&#x3e; and &#x3c;11-20&#x3e; directions, at an offcut angle in a range that is from about 0.2 to about 10 degrees, wherein the surface has a RMS roughness measured by 50&#xd7;50 &#x3bc;mAFM scan that is less than 1 nm, and a dislocation density that is less than 3 E6 cm. The substrate may be formed by offcut slicing of a corresponding boule or wafer blank, by offcut lapping or growth of the substrate body on a corresponding vicinal heteroepitaxial substrate, e.g., of offcut sapphire. Both upper and lower surfaces may be offcut. The substrate is usefully employed for homoepitaxial deposition in the fabrication of III-V nitride-based microelectronic and opto-electronic devices.

Vicinal gallium nitride substrate for high quality homoepitaxy

A Group III-V nitride microelectronic device structure including a delta doped layer and/or a doped superlattice. A delta doping method is described, including the steps of: depositing semiconductor material on a substrate by a first epitaxial film growth process; terminating the deposition of semiconductor material on the substrate to present an epitaxial film surface; delta doping the semiconductor material at the epitaxial film surface, to form a delta doping layer thereon; terminating the delta doping; resuming deposition of semiconductor material to deposit semiconductor material on the delta doping layer, in a second epitaxial film growth process; and continuing the semiconductor material second epitaxial film growth process to a predetermined extent, to form a doped microelectronic device structure, wherein the delta doping layer is internalized in semiconductor material deposited in the first and second epitaxial film growth processes.

Doped group III-V nitride materials, and microelectronic devices and device precursor structures comprising same

A boule formed by high rate vapor phase growth of Group III-V nitride boules (ingots) on native nitride seeds, from which wafers may be derived for fabrication of microelectronic device structures. The boule is of microelectronic device quality, e.g., having a transverse dimension greater than 1 centimeter, a length greater than 1 millimeter, and a top surface defect density of less than 10defects cm. The Group III-V nitride boule may be formed by growing a Group III-V nitride material on a corresponding native Group III-V nitride seed crystal by vapor phase epitaxy at a growth rate above 20 micrometers per hour. Nuclear transmutation doping may be applied to an (Al,Ga,In)N article comprises a boule, wafer, or epitaxial layer.

III-V nitride substrate boule and method of making and using the same

The present invention relates to various switching device structures including Schottky diode (), P&#x2014;N diode, and P&#x2014;I&#x2014;N diode, which are characterized by low defect density, low crack density, low pit density and sufficient thickness (&#x3e;2.5 um) GaN layers () of low dopant concentration (&#x3c;1E16 cm&#x2212;3) grown on a conductive GaN layer (). The devices enable substantially higher breakdown voltage on hetero-epitaxial substrates (&#x3c;2 KV) and extremely high breakdown voltage on homo-epitaxial substrates (&#x3e;2 KV).

A III-V nitride, e.g., GaN, substrate including a (0001) surface offcut from the &#x3c;0001&#x3e; direction predominantly toward a direction selected from the group consisting of &#x3c;10-10&#x3e; and &#x3c;11-20&#x3e; directions, at an offcut angle in a range that is from about 0.2 to about 10 degrees, wherein the surface has a RMS roughness measured by 50&#xd7;50 &#x3bc;mAFM scan that is less than 1 nm, and a dislocation density that is less than 3E6 cm. The substrate may be formed by offcut slicing of a corresponding boule or wafer blank, by offcut lapping or growth of the substrate body on a corresponding vicinal heteroepitaxial substrate, e.g., of offcut sapphire. The substrate is usefully employed for homoepitaxial deposition in the fabrication of III-V nitride-based microelectronic and opto-electronic devices.

A boule formed by high rate vapor phase growth of Group III-V nitride boules (ingots) on native nitride seeds, from which wafers may be derived for fabrication of microelectronic device structures. The boule is of microelectronic device quality, e.g., having a transverse dimension greater than 1 centimeter, a length greater than 1 millimeter, and a top surface defect density of less than 10defects cm. The Group III-V nitride boule may be formed by growing a Group III-V nitride material on a corresponding native Group III-V nitride seed crystal by vapor phase epitaxy at a growth rate above 20 micrometers per hour.

A III-nitride electronic device structure including doped material, an active region and a barrier material arranged to suppress transport of dopant from the doped material into the active region, wherein the barrier material comprises high-Al content AlGaN, wherein x+y=1, and x&#x2267;0.50. In a specific aspect, AIN is used as a migration/diffusion barrier layer at a thickness of from about 5 to about 200 Angstroms, to suppress flux of magnesium and/or silicon dopant material into the active region of the III-nitride electronic device, e.g., a UV LED optoelectronic device.

III-nitride optoelectronic device structure with high Al AlGaN diffusion barrier

A III&#x2013;V nitride, e.g., GaN, substrate including a (0001) surface offcut from the &#x3c;0001&#x3e; direction predominantly toward a direction selected from the group consisting of &#x3c;10-10&#x3e; and &#x3c;11-20&#x3e; directions, at an offcut angle in a range that is from about 0.2 to about 10 degrees, wherein the surface has a RMS roughness measured by 50&#xd7;50 &#x3bc;mAFM scan that is less than 1 nm, and a dislocation density that is less than 3E6 cm. The substrate may be formed by offcut slicing of a corresponding boule or wafer blank, by offcut lapping or growth of the substrate body on a corresponding vicinal heteroepitaxial substrate, e.g., of offcut sapphire. The substrate is usefully employed for homoepitaxial deposition in the fabrication of III&#x2013;V nitride-based microelectronic and opto-electronic devices.

A boule formed by high rate vapor phase growth of Group III-V nitride boules (ingots) on native nitride seeds, from which wafers may be derived for fabrication of microelectronic device structures. The boule is of microelectronic device quality, e.g., having a transverse dimension greater than 1 centimeter, a length greater than 1 millimeter, and a top surface defect density of less than 10 defects cm . The Group III-V nitride boule may be formed by growing a Group III-V nitride material on a corresponding native Group III-V nitride seed crystal by vapor phase epitaxy at a growth rate above 20 micrometers per hour.

A method of forming a (gallium, aluminum, indium) nitride base layer on a substrate for subsequent fabrication, e.g., by MOCVD or MBE, of a microelectronic device structure thereon. Vapor-phase (Ga, Al, In) chloride is reacted with a vapor-phase nitrogenous compound in the presence of the substrate, to form (Ga, Al, In) nitride. The (Ga, Al, In) nitride base layer is grown on the substrate by HVPE, to yield a microelectronic device base comprising a substrate with the (Ga, Al, In) nitride base layer thereon. The product of such HVPE process comprises a device quality, single crystal crack-free base layer of (Ga, Al, In) N on the substrate, in which the thickness of the base layer may, for example, be on the order of 2 microns and greater and the defect density of the base layer may, for example, be on the order of 1E8 cm or lower. Microelectronic devices thereby may be formed on the base layer, over a substrate of a foreign (poor lattice match) material, such as sapphire. Devices which may be fabricated utilizing the HVPE base layer of the invention include light emitting diodes, detectors, transistors, and semiconductor lasers.

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Wake Forest, NC, United States of America

Jeffrey S Flynn